Variable-speed belt drive



March 11, 1947.

A. F. ALEXANDER 2,417,047

VARIABLE SPEED BELT DRIVE Filed 0G13. 25, 1945 5&5 1 V T7.

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Patented Mar. l1, 1947 UNITED STATES PATENT OFFICE i I l 2,417,047

VARIABLE- SPEED BEL'Ql` DRIVE Arthur F. Alexander, Cleveland, OhioApplication OctOber 25, 1945, Serial N0. 624,381

This invention, relates to improvements in power units, vand has todowith the provision of a unitarymachine embodying an electric motor andcapable of delivering power at an infinite number of speeds.

One of the objects of the invention is the provision of a compact,nicelybalanced unit more or less symmetrical in shape and appearance.

Another object is the' provision of a standard power unit adapted todeliver power at a multiplicity of speeds and suited for application andmounting in the place of the conventional single speed electric motor. e

Still another object is the provision of a unit of the charaster statedembodying simple and readily adjusted change speed means, capable ofactuation during operation of the unit.

Other objects and features of novelty will appear as I proceed with thedescription. of that embodiment of the invention which, for the purposesof the present application, I have illustrated in theaccompanyingdrawing, in which Fig. 1 is a front elevational view, partly in verticalsection, of a unit embodying the invention.

Fig. 2 is a detail planview taken substantially on the line 2-2 of Fig.1, and` A A Fig. 3 is a detail sectional view taken substantially on theline 3-4-3 of Fig. 1. I

In the drawings thereis shown a housing comprising a cylindrical member,I mounted on feet II, vertical side plates I2 andl I3 and a bracket I4mounted on the cylindrical member Ill. The housing may comprise alsodished end members |5 and I6'. Preferablythe upper part of the structureis enclosed in asheet-m'etal hood which, however, is not an essentialpartof the unit and is omitted from the illustration herein in theinterest of simplification. e

In thel wall plates I2 and I3 there are mounted aligned antifrictionbearings I1 and I8, in which is journaled a shaft I8 that is hollow ortubular for at least a portion of its length. On this hollow shaft iskeyed the rotor 20 of a'nelectric motor shown in outline only in thedrawing. -On this hollow shaft outside the wall plate I2 there is asplit V pulley' comprising the element 2| which is secured to the shaftand the element 22 which is free to move axially ofthe shaft but turnswith the shaft. e, I

Another antifriction bearing 23 in wall plate I3. and a bearing 24 inframe member IBare mounted in alignment with bearings I1 and I8 andsupport a shaft 25, hereinafter referred to as the output shaft, whichisal's'o hollow for arportin lof 9 Claims. (Cl. 'I4-230.17)

one element 26 of which is fixed upon the shaft telers@ ,Qn ,tlllisbeftthere ielaplitv puller4 65 and the other element 21 of which is slidablelengthwise onthe shaft. Y

Puuey elements 2z and 21 are `subStanuauy identical although reversed inposition, and each has a projecting hub 28 in which is mounted adiametrically disposed pin 29 that extends through longitudinal slots 30in the hollow shaft I9. Each of these pins also extends through adiametrical hole in a hardened cylindrical block 3|, the pin for element22 being slidable within hollow shaft I9 and that for element 21 beingslidable in the hollow part of shaft 25. Between the two blocks 3| thereis a rod or shaft 32 for transmitting longitudinal movement from element22 to element 21 or vice versa, and because these lelements rotate atdifferent speeds balls 33 or other suitable antifriction bearings may beemployed between the shaft 32 and each of the blocks 3|. It is alsowithin the purview of the invention to omit the right hand block 3l andits associated ball 33, in which event the corresponding pin 29 wouldextend through the shaft 32, and that shaft would necessarily rotate atthe speed of hollow shaft I9. 1

In ,the bracket I4 there are two antifriction bearings 40 and-4|, inwhich there is journaled a, sleeve 42 which projects far enough beyondthose bearings to receive the inner elements 43 and 44 of two split Vpulleys. These pulley elements are secured to the sleeve as shown in thedrawing and have hub portions engaging the inner races of bearings 40-and 4|, whereby the sleeve and the pulley elements mounted thereon areheld against axial movement. A stem 45 of greater length than the sleeveis mounted to slide therein. Its projecting ends are reduced in diameterand receive the remaining elements 4Band 41 of the split V pulleyscarried by this countershaft assembly. The elements 4B and 41 may befixed upon the stem by means of nuts 48 threaded onto thereduced endsthereof.

Suitable means are provided for moving stem 4 5 endwisefor the purposeof expanding the split V pulley at one end of the assembly, whilecontracting that at the opposite. end. Preferably this means comprises apin 49V mounted in a diametrical hole` in the stem, projecting throughslots 50 in sleeve 42 and extending into holes in a fianged collar 5|which surrounds and is slidable upon the sleeve 42. This arrangementinsures the rotation' of the sleeve and stem together while permittingrelative longitudinal movement.` A ballbearing l5 2 surrounds collar 5I,and its inner race is clamped against the flange of the' collar by meansof a ring nut 53 threaded upon the collar. The outer race of this ballbearing extends into a groove 54 ln the top of a block 55 which has adownwardly extending pivot 56 that turns in a socket in an upwardlydirected extension 51 of a bell crank lever 58 pivoted at 59 to a boss6U forming part of bracket I4. The other end of bell crank lever 58 hasa slot '6I therein which receives a pin 62 depending from a collar 63that surrounds a rod 64 between a shoulder 65 on the rod and the hub 66of a hand wheel 61 pinned to the rod 64. The rod has a threaded portion,as shown in Fig. 2, which projects through an internally threaded ear 68on bracket I4. By this means obviously the ball bearing 52 and collarmay be moved on the sleeve 42 longitudinally thereof, thereby shiftingthe outer elements of the two split V pulleys.

A V-belt connectsvthe motor shaft pulley with the right hand pulley ofthe countershaft and a V-belt 1I connects the left hand pulley of thecountershaft with the pulley of the output shaft. Shaft I9 projectsbeyond the housingy member I5 and may be used to drive any machine orpiece of apparatus which is suitable'for operation at constant speed.Shaft 25 extends beyond the housingmember I6, and from it may be takendriving power at. a wide variation of speeds either below or above motorspeed, or at motor speed, as will be evident to those skilled in theart. y Y

When the stem 45 is adjusted to the position shown in the drawingfthespeed of the output shaft 25 is substantially maximum, or of the orderof double motor speed. As the operator turns hand wheel 61 *to move stem45 toward the left the pulley element 46'ispdrawn toward the pulleyelement 43, causing the belt 1-0 to run upon a larger diameter part ofthe split pulley 43, 46. At the same time the pulley element 41movesaway from the element 44 permitting the belt 1I to run upon asmaller diameter part of the split pulley. AAsthe belt 1D ridesoutwardly upon the pulley 43, 46 it exerts wedging pressure tending toseparate pulley elements 2| and 22, and inasmuch as element 2| is fixedon its shaft, element 22 is caused to `move toward the left. In thisoperation'both bights of belt 10 move to the left thev same amount, andproper alignment is preserved. The movement of pulley element 22` towardthe left transmits movement through the blocks 3l and the shaft 32 tothepulleyy element 21, thereby narrowing the space between the elements ofthe output pulley and causing the belt `1I to `ride or travel outwardlyupon the `pulley and at the same time to shift toward the left. Theexpansion of the pulley 44, 41 due to movement of stem 45 permits theupper bight of the belt to run upon a smaller diameter 4part of thatpulley in response to belt pressureV resulting from the contraction ofpulley .26, V21 and also `permits the upper bight of the belt to move tothe left an amount corresponding with -the movement ofthe lower bight.

The maintenance of the belts throughout the different speed adjustmentsso that they always run in planes perpendicular to the vshafts resultsfrom maintaining the right hand pulley element xed on one' vshaft andtheleft handelement fixed on the other shaft. In the case-of thevcountershaft -the two inside 'elements arexed Aagainst movement7longitudinally in a manner` previously described, and inthe lcase ofthe llowerfsh'afts I9 andi-25 the outside --elements are-fixed.. :As Ltothe.

4 latter shafts this may be accomplished in various ways, but forpurposes of illustration movement of shaft 25 to which element 26 isfastened is prevented by contact of the hub part of element 2'6 with theinner race of bearing 24 and by setting the inner race of bearing 23into a shouldered recess in the shaft. Shaft I9, to which pulley element2| is secured, is shown held against longitudinal movement by means of asplit ringf15 secured to. thehousing and engaging in an annular groove16 in the shaft.

Having thus described my invention, I claim:

1. In a power unit, a housing, aligned motor and output shafts, a rotoron said motor shaft, a split V pulley on said motor shaft at one side ofsaid rotor, a split V pulley on said output shaft at the other side ofsaid rotor, a countershaft mounted on said housing carrying split Vpulleys in radial alignment with said motor and output shaft pulleysrespectively, and means for expanding one of said countershaft pulleyswhile contracting the other.

2. A power unit according to claim 1, wherein the said motor shaft ishollow and one element of its split pulley is connected' through saidhollow shaft with one element 0f the output shaft pulley forcommunicating movement from one of said elements to the other.

3. A power unit according to claim 1, wherein the said motor shaft ishollow, and comprising connecting means including a rod extendingthrough said hollow shaft for transmitting movement from the insideelement of one pulley to the inside element of the other pulley' whilepermitting relative rotation.

4. A power unit according'to claim 1, wherein said countershaftcomprises ,a sleeve member at the ends of which the inside elements ofthe two countershaft pulleys are xed, a stem member extending throughsaid sleeve member and carrying at its extremities the remainingelements of said pulleys, and adjusting means disposed between saidpulleys formoving one of said members endwise.

5. A power unit according.' to claim 1, wherein said countershaftcomprises a sleeve at the Vends of which the inside elements of the twocountershaft pulleys are fixed and a stem extending through said sleeveand carrying at its extremities the outermost elements of said pulleys,and adjusting means operative through a slot in said sleeve for movingsaid stem endwise.

6. In a power unit, a housing, ahollow'motor shaft and a hollow'outputshaft, aligned bearings for leach of said shafts, va rotor on said metershaft, avsplit V pulley on saidgmotor shaft at one side of said rotor, asplit V pulley on said output shaft at the other side of said rotor, acountershaft mounted on said housing carrying split V pulleys in radiallalignment respectively with said motor and output shaft pulleys, meansfor expanding one countershaft pulley while contracting the other, andmeans comprising a rod mountedin--said hollow shafts'for transmittingmove'- ment longitudinally thereof from an element of the pulley on onehollow shaft' to an element of the pulley on the other hollow,v shaftwhile permitting relative rotation of said pulleys.

'1. Apower unit according to claim 1, wherein said countershaftAcomprises a sleeve, a pair of bearings in which said sleeve isjournaled, the insidel elements of the two countershaft pulleys beingVfixed -upon the ends of said sleeve adjacent the outer` sides-of saidybearingaa :stem extending throulirli sa'iclfsleeve and-carrying atits'ex- 5 tremities the outer elements of said pulleys, and adjustingmeans for moving said stem endwise.

8. A power unit according to claim-1, wherein said countershaftcomprises a sleeve, a pair of bearings in which said sleeve isjournaled, the inside elements of the two countershaft pulleys beingfixed upon the ends of said sleeve adjacent the outer1 sides of saidbearings, a stem extending through said sleeve and carrying at its eX- Ytremities the outer elements of said pulleys, and adjusting means formoving said stem endwise comprising a pin fixed in said stem betweensaid pulleys and projecting through slots in said sleeve.

9. In a power unit, a housing, a motor shaft and an output shaft inalignment, a rotor on said motor shaft, a split V pulley on said motorshaft at one side of said rotor, a split V pulley on said output shaftat the other side of said rotor, a countershaft mounted on said housingcarrying split V pulleys in radial alignment With said motor and outputshaft pulleys respectively, said countershaft comprising a sleeve heldagainst end- Number Name Date v 2O '2,179,053 Reeves Nov. 7, 19392,351,148 Rafter June 13, 1944 Wise movement, the inner elements of thecountershaft pulleys being mounted on said sleeve, said countershaftcomprising also a 'stern extending through said sleeve andlongitudinally movable therein, the outer elements of the countershaftpulleys being mounted upon said stem, said motor shaftand said outputshaft being held against longitudinal movement, and the outer pulleyelements on said last named shafts being xed thereupon while the innerpulley elements are free to move endwise of the shafts.

ARTHUR F. ALEXANDER.

REFERENCES CITED Y The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

